1. Field of the Invention
The present invention relates to a compact zoom lens and, more particularly, to a compact zoom lens which comprises a positive, negative and positive lens groups constituting a vari-focal lens group and a positive lens group constituting a relay lens group, i.e., four lens groups in total, and for which the field angle is about 16 degrees to 35 degrees and telephoto ratio is smaller than 1.
2. Description of the Prior Art
Among so-called mechanical compensation type zoom lenses which are widely known, there are zoom lenses having lens configuration similar to the above and arranged to vary the focal length by moving the second lens group in the direction of an optical axis thereof and to move the third lens group so that it forms a locus concave toward the object side in order to compensate the variation of final image position to be caused by the above-mentioned movement of the second lens group. For this kind of zoom lenses, especially for such zoom lenses for which the range of focal length is 70 to 150 mm when converted to 35 mm format (film size 24 mm.times.36 mm) and for F number about F:4, it is desirable to make the telephoto ratio (i.e., the value obtained by dividing the distance from the front lens surface to the final image surface by the focal length at the longest focal length) smaller than 1 for the purpose of making the lens compact. However, it has been difficult to do so from the view point of correction of aberrations.